1. Field of the Invention
The present invention relates to a device for correcting a tremble of a focused image of an object caused by an oscillation of an optical device due to, for example, a hand tremble.
2. Description of the Related Art
Conventionally, there is known an optical device, for example, a camera or binoculars, with which a correction device, for correcting a focused image tremble due to for example a hand tremble and so on, is provided. An amount of a tremble of the optical device is detected by the correction device. The correction device drives a correcting optical system such that the amount of the tremble is canceled. Namely, the correction optical device is driven following the focused image tremble.
There is a correctable range of the correction optical system, which is defined by a structure of a driving device of the correction optical system. When the focused image tremble occurs out of the correctable range, it is impossible to drive the correction optical system so as to follow the focused image tremble. Accordingly, the correction lens is stopped if the focused image tremble occurs out of the correctable range, and the correction optical system remains stopped while the situation in which the focused image tremble is out of the correctable range continues.
When the focused image tremble returns within the correctable range, the driving of the correction optical system is restarted. However, before the correction optical system can be driven so as to follow the focused image tremble, the correction optical system must be moved from the position at which it stopped when the focused image tremble extended beyond the correctable range. Accordingly, between the moment at which the focused image tremble returns within the correctable range and a moment at which the correction optical system restarts to follow the focused image tremble, there is an expected time lag. Therefore, the effectiveness of the correction of the focused image tremble is extremely reduced.
Further, there are some cameras in which the correction of the focused image tremble is carried out before an exposure period. The correction of the focused image tremble should be most effectively carried out during the exposure period. Nevertheless, if a relatively large focused image tremble occurs before the exposure period and the correction optical system is driven close to a boundary of the correctable range, a range, in which the correction optical system is able to be driven during the exposure period, is extremely limited. Accordingly, the effectiveness of the correction of the focused image is not high enough during the exposure period, so that a quality of a photographed image is lowered.
Therefore, an object of the present invention is to provide a device for correcting the focused image tremble, in which the correction is restarted in an instant when the focused image tremble returns within the correctable range. Further, another object of the present invention is to provide a device for correcting the focused image tremble, in which the effectiveness of the correction is sustained during a period of recording an object image even if the large focused image tremble occurs while the object image is not being recorded.
In accordance with an aspect of the present invention, there is provided a device for correcting a tremble of a focused image comprising: a tremble detector that detects a direction and a quantity of a tremble of an optical device; a correction optical system that is included in an imaging optical system and corrects a tremble of an optical image which is imaged by the imaging optical system; a driving device that drives the correction optical system; a tremble position detector that detects an actual tremble position on a focal plane, through which an optical axis of other optical systems included in the imaging optical system pierces and on which the optical image is imaged by the imaging optical system, the actual tremble position being moved in accordance with the tremble of the optical device, the optical axis of the other optical systems piercing through a center of the focal plane, when an optical axis of the correction optical system is positioned at an original point at which the optical axis of the correction optical system is coaxial with the optical axis of the other optical systems; a controlling system that calculates driving data of the correction optical system based on the actual tremble position in order to cancel the tremble, and controls the driving device based on the driving data; and a judging system that judges whether the actual tremble position is within a correctable range on the focal plane, which is defined by the controlling system.
If the judging system judges that the actual tremble position is out of the correctable range, an intersection, of a boundary of the correctable range and a straight line connecting the center of the focal plane and the actual tremble position, is supposed to be a tremble position by the controlling system, and the controlling system calculates driving data of the correction optical system based on the supposed tremble position.
Preferably, the correctable range is defined as an area bounded by a trace of positions at which the correction optical system is driven as far as possible from the original point.
Preferably, the correctable range is set to be smaller than a range, a boundary of which is defined by a trace of positions at which a supporting member of the correction optical system is not movable, being in contact with other members of the optical device.
Preferably, the correctable range is a circle, a center of which is the original point.
Preferably, the judging system judges whether the actual tremble position is within the correctable range by comparing a length between the actual tremble position and the original point with a radius of the circle.
Preferably, when the controlling system calculates a displacement to the intersection of the supposed tremble position, the controlling system extracts direction data which indicates a direction to the actual tremble position, calculates only a quantity of the displacement to the intersection based on a displacement to the actual tremble position out of the correctable range, and adds the direction data to the quantity of the displacement to the intersection.
In accordance with another aspect of the present invention, there is provided a device for correcting a tremble of a focused image comprising: a tremble detector that detects a direction and a quantity of a tremble of an optical device; a correction optical system that is included in an imaging optical system and corrects a tremble of an optical image which is imaged by the imaging optical system; a driving device that drives the correction optical system; a tremble position detector that detects an actual tremble position on a focal plane, through which an optical axis of other optical systems included in the imaging optical system pierces and on which the optical image is imaged by the imaging optical system, the actual tremble position being moved in accordance with the tremble of the optical device, the optical axis of the other optical systems piercing through a center of the focal plane, when an optical axis of the correction optical system is positioned at an original point at which the optical axis of the correction optical system is coaxial with the optical axis of the other optical systems; a controlling system that calculates driving data of the correction optical system based on the actual tremble position in order to cancel the tremble, and controls the diving device based on the driving data; and a judging system that judges whether the actual tremble position is within a correctable range on the focal plane, which is defined by the controlling system.
If the judging system judges that the actual tremble position is out of the correctable range, a point on a boundary of the correctable range, which is closest to the actual tremble position, is supposed to be a tremble position by the controlling system, the controlling system controlling the driving system such that a displacement of the optical axis of the other optical systems to the supposed tremble position is able to be canceled.
In accordance with another aspect of the present invention, there is provided a device for correcting a tremble of a focused image, that is provided for a camera including a photographing optical system, and a photographing control system which records an optical image, imaged on a photographing medium, on the photographing medium by controlling an imaging capturing operation comprising: a tremble detector that detects a direction and a quantity of a tremble of the camera; a correction optical system that is included in the photographing optical system and corrects a tremble of the optical image; a driving device that drives the correction optical system; a tremble position detector that detects a tremble position on a focal plane, through which an optical axis of other optical systems included in the photographing optical system pierces and on which the optical image is imaged by the imaging optical system, the position being moved in accordance with the tremble of the camera, the optical axis of the other optical systems piercing through a center of the focal plane, when an optical axis of the correction optical system is position at an original point at which the optical axis of the correction optical system is coaxial with the optical axis of the other optical systems; and a controlling system that calculates driving data of the correction optical system based on the tremble position in order to cancel the tremble, and controls the driving device based on the driving data.
The controlling system controls the driving device such that a first correctable range, of the correction optical system on the focal plane under a first state in which the camera is under a standby state, is smaller than a second correctable range, of the correction optical system on the focal plane under a second state in which the camera is under an image capturing state.
Preferably, the second correctable range is defined as an area bounded by a trace made by driving the correction optical system so as to be positioned as far as possible from the original point.
Preferably, the second correctable range is set to be smaller than a range, a boundary of which is defined by a trace of positions at which a supporting member of the correction optical system is not movable, being in contact with other members of the camera.
Preferably, the first correctable range and the second correctable range are a circle, a center of which is the original point.
Preferably, if the tremble is out of the first correctable range under the first state, the correction optical system is stopped, and the correction optical system is restarted to be driven for correcting the tremble from a position at which the correction optical system was stopped, when the image capturing operation begins.
Preferably, the photographing control system further comprises a photometric device that carries out a photometric operation in accordance with an operation of an operating member mounted on the camera, and the correction optical system is driven within the first correctable range during a period in which the photometric operation is being carried out.